diff --git a/documentation/ref-manual/ref-classes.xml b/documentation/ref-manual/ref-classes.xml
index e80996df55..af07b144d6 100644
--- a/documentation/ref-manual/ref-classes.xml
+++ b/documentation/ref-manual/ref-classes.xml
@@ -115,7 +115,17 @@
     </para>
 
     <para>
-        To use this class, you need to define a number of variables.
+        To use this class, you need to define a number of variables:
+        <itemizedlist>
+            <listitem><para><link linkend='var-ALTERNATIVE'><filename>ALTERNATIVE</filename></link>
+                </para></listitem>
+            <listitem><para><link linkend='var-ALTERNATIVE_LINK_NAME'><filename>ALTERNATIVE_LINK_NAME</filename></link>
+                </para></listitem>
+            <listitem><para><link linkend='var-ALTERNATIVE_TARGET'><filename>ALTERNATIVE_TARGET</filename></link>
+                </para></listitem>
+            <listitem><para><link linkend='var-ALTERNATIVE_PRIORITY'><filename>ALTERNATIVE_PRIORITY</filename></link>
+                </para></listitem>
+        </itemizedlist>
         These variables list alternative commands needed by a package,
         provide pathnames for links, default links for targets, and
         so forth.